1. Field of the Invention
Exemplary embodiments of the present invention relate to a network system and method for relaying communication between devices.
2. Description of the Related Art
Recent remarkable advancement of home networking technologies has provided a high degree of convenience to users. However, despite this home networking boost, home networks built in old, obsolete apartment buildings have difficulty in connecting to the Internet, or tend to suffer low quality communication when they are connected to the Internet, thereby causing user inconvenience.
FIG. 1 illustrates an example of a related art indoor home network 110.
Referring to FIG. 1, the indoor home network 110 includes a set-top box (STB) 112, an interphone 114, and a plurality of home network devices 112a through 112c and 114a through 114c respectively connected to the STB 112 and the interphone 114. The plurality of home network devices 112a through 112c and 114a through 114c are hereinafter respectively referred to as a TV 112a, a PC 112b, an Internet phone 112c, a lighting switch 114a, a heating controller 114b, and a gas valve controller 114c. More specifically, the STB 112 is connected to the Internet 130, the TV 112a, the PC 112b, and the Internet phone 112c via a Local Area Network (LAN), relaying communication between the Internet 130 and each of the TV 112a, the PC 112b, and the Internet phone 112c. 
The interphone 114 is connected to security surveillance equipment 120, lighting switch 114a, heating controller 114b, and gas valve controller 114c using RS-485 communication to communicate with security surveillance equipment 120 and control the lighting switch 114a, heating controller 114b, and gas valve controller 114c. 
The security surveillance equipment 120 is linked to a plurality of different home networks including the home network 110, and in particular, to each of a number of interphones within different home networks to control entry and access to a building. In this case, the security surveillance equipment 120 uses an entry access control device 122 and a closed circuit television (CCTV) 124 for entry and access control.
The configuration shown in FIG. 1 has the problem that services do not interact between the Internet phone 114 and the STB 112 because the security surveillance equipment 120 connected to the interphone 114 via RS-485 is not connected to the Internet 130 while the STB 112 is connected thereto using the LAN.
FIG. 2 illustrates another example of a related art indoor home network 210.
For convenience of explanation, the home network devices 112a through 112c and 114a through 114c are not shown in FIG. 2. Referring to FIG. 2, an STB 212 and an interphone 214, within the indoor home network 210, are respectively connected to content server 230 and security surveillance equipment 220 using LAN communication.
Both of the STB 212 and the security surveillance equipment 220 are connected to the Internet via a first communication network for communication, so that services can interact between the STB 212 and the interphone 214. For example, this configuration enables a user to control a gas valve controller connected to the interphone 214 through a TV connected to the STB 212.
The first communication network is an existing network that has problems such as narrow bandwidth and unguaranteed Quality of Service (QoS), thereby causing an inconvenience when the STB 212 receives real-time broadcast content or large size content over the Internet. To overcome this problem, an approach to receiving real-time broadcast content or large size content from a content server 230 has been proposed. That is, the configuration shown in FIG. 2 includes the content server 230 that stores large size content. The STB 212 receives real-time broadcast content or large size content from the content server 230. However, if content that the STB 212 desires to receive is not stored in the content server 230, this approach suffers still the above problem because the STB 212 still has to receive the desired content from the Internet via the first communication network.
FIG. 3 illustrates another example of a related art indoor home network 310.
Referring to FIG. 3, unlike in the home network 210 of FIG. 2, an STB 312 is connected to the Internet 330 via a second communication network with guaranteed QoS and wider bandwidth than a first communication network. That is, in this example, the indoor home network 310 is connected to the Internet 330 via the second communication network so as to allow communication with the Internet 330 using the high quality second communication network instead of the first communication network previously built by a user.
The configuration shown in FIG. 3 allows the STB 312 to communicate with the Internet 330 using the wide bandwidth second communication network, thus eliminating the need for the content server (230 in FIG. 2) while sustaining entry and access control services provided via the first communication network.
However, the home network 310 is configured such that the STB 312 is connected to the Internet 330 via the second communication network while an interphone 314 is connected to security surveillance equipment 320 connected to the Internet via the first communication network. Thus, this configuration has a drawback in that services cannot interact between the STB 312 and the interphone 314 due to the use of different communication networks for connection with the Internet 330. That is, unlike the home network 210 shown in FIG. 2, the home network 310 cannot allow a user to control a device such as a gas valve controller connected to the interphone 314 through a device such as a TV connected to the STB 312.